London's new "bendy buses" are to be inspected every day after a third one in four months caught fire while carrying passengers.

In the latest incident, a No 436 bus was gutted after flames were seen pouring out of the engine at the back of the vehicle as it travelled past the Hilton Hotel on Park Lane.

Passengers were evacuated before a fireball engulfed the entire length of the 60ft bus on Saturday evening.

Within a matter of minutes it was left a burned-out shell with only the metal chassis remaining.

A fire service spokesman said: "There is obviously a mechanical fault there."

Transport for London (TfL) was holding emergency discussions with the bus makers, Evo Bus, a subsidiary of Mercedes.

TfL today said the buses will now be inspected every day and are to be fitted with automatic fire-fighting equipment.

A TfL spokesman said: "We are in talks with Mercedes to ascertain exactly what went wrong in all three fires.

"We have agreed these buses will be inspected nightly.

Mercedes have also agreed to fit existingand future buses with fire suppressingequipment." But he said the buses would not be withdrawn. TfL has bought 120 of the buses at nearly £200,000 each to cope with increased demand.

With a capacity of 140, they can carry twice the number of passengers as the existing Routemasters - but only three Routemasters have been destroyed by fire in their 45 years of service.

In December, passengers fled after fire took hold of a "bendy bus" on Edgware Road.

The fire started when a pipe snapped and the oil it was carrying ignited.

Last month a bus in Camberwell was also destroyed by fire when an air pipe cracked and damaged wiring.

London Fire Brigade said they have passed detailed reports to TfL on the previous fires.

Andrew Bosi, chairman of the pressure group Capital Transport Campaign, said: "Until we know what has happened these buses should be taken off the road."